Humalog is one of Lilly’s flagship drugs, generating sales of $641 million in the second quarter alone. According to PMLive.com, Humalog was the 35th highest grossing drug in the world in 2014.

Much of that revenue is due to massive price increases. As Sanders points out, Humalog’s inflation-adjusted price has grown from $21 per vial in 1996 to $255 per vial this year. That’s an 1100% price increase in twenty years, during which Lilly has boosted the price over two dozen times.

Today marks the second time in the past few weeks that Sanders has publicly pointed shamed drug industry pricing. Last month, his tweet targeting high-flying Ariad Pharmaceuticals caused the company’s stock to plummet 14% in a matter of minutes. We warned investors back then to expect more criticism and intervention from politicians, and more share price crashes as a result.

Eli Lilly shares fell $1.13 (-1.53%) to $72.71 in Tuesday afternoon trading. Year-to-date, LLY has plunged 13.65%, versus a 3.27% gain in the benchmark S&P 500 during the same period.